To R. F. Cooke   21 July 1880

My dear Sir

I must take the risk & loss on my own shoulders. As I have made some money by science, I must now lose some for science. I will have 1000 copies printed off & from what you say charge 15^s.¹ As soon as a moderate time has elapsed for the sale of whatever copies may be sold I will settle with you; & I shall, as I believe, in the course of a few years be partly or wholly repaid by future sales.

With many thanks for all your kind consideration of this affair, I remain | Yours sincerely | Ch. Darwin